`LANGUAGE=C` is not enough, `LC_ALL=C` is needed as the environment
variable that overrides all the other localization settings.
e.g.
```bash
$ LANGUAGE=C id foobar
id: ‘foobar’: no such user
$ LC_ALL=C id foobar
id: 'foobar': no such user
```
* replace `LANGUAGE` with `LC_ALL` as environment variable in the tests
* fix the the date string of affected uutils
* replace `‘` and `’` with `'`
A lot of tests depend on GNU's coreutils to be installed in order
to obtain reference values during testing.
In these cases testing is limited to `target_os = linux`.
This PR installs GNU's coreutils on "github actions" and adjusts the
tests for `who`, `stat` and `pinky` in order to be compatible with macOS.
* `brew install coreutils` (prefix is 'g', e.g. `gwho`, `gstat`, etc.
* switch paths for testing to something that's available on both OSs,
e.g. `/boot` -> `/bin`, etc.
* switch paths for testing to the macOS equivalent,
e.g. `/dev/pts/ptmx` -> `/dev/ptmx`, etc.
* exclude paths when no equivalent is available,
e.g. `/proc`, `/etc/fstab`, etc.
* refactor tests to make better use of the testing API
* fix a warning in utmpx.rs to print to stderr instead of stdout
* fix long_usage text in `who`
* fix minor output formatting in `stat`
* the `expected_result` function should be refactored
to reduce duplicate code
* more tests should be adjusted to not only run on `target_os = linux`
This closes#2181.
`who --lookup` is failing with a runtime panic (double free).
Since `crate::dns-lookup` already includes a safe wrapper for `getaddrinfo`
I used this crate instead of further debugging the existing code in
utmpx::canon_host().
* It was neccessary to remove the version constraint for libc in uucore.
